Starting motor-converter.



EATENTED JAN. 21, 1908. RSON. STARTING MOTOR C ONVU'RTEE.

E. P. W. ALEXANDE APPLICATION FILED 31, 1907.

mm NA E V FL -1 Hw d N V R Emu.

WITNESSES rm'1' Om approaches its normal speed and the voltage impressed on the field magnet D diminishes in frequency and finally becomes unidirec tional, the magnetization of the field magnet builds up sufficientl to lock the motor converter at its normal speed when that speed is reached. The reduction in the effective number of field turns of the rotary converter by cutting out a portion of the Winding assists materially in enabling it to build up its magnetization fast enough to hold the converter at normal speed As soon as the converter is operating at normal speed, switch G is thrown to the right, so as to connect the entire field winding in circuit, switch F is closed, short-circuiting resistance E, and the direct-current load-circuit may then be closed.

It will he understood that I have illus trated my invention diagrammatically tor the sake of slmplicity, and that in practice any well known constructions may be employed for the machines and controlling devices.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

v 1. In combination with a motor-converter comprising an induction motor and rotary converter mechanically and electrically couled, means for reducing the eiiective numlier of turns of the field winding of the rotary converter at starting.

2. In combination witha motor-converter comprising an induction motor and rotary converter with armatures mechanically coupled and electrically connected in series, a starting resistance in series with said armatures, a short-circuiting switch therefor, and means for reducing the effective number of turns of the field winding of the rotary converter at starting.

3. In combination with a motor-converter comprising an induction motor and rotary converter mechanically and electrically coupled, a switch arranged to cut out a portion of the field winding of the rotary converter at starting. a

4. In combination with a motorconverter comprising an induction motor and rotary converter with armatures' mechanically coupled and electrically connected in series, a starting resistance carried by said armatures and connected in series with the armature windings, a short-circuiting switch therefor, and means for reducing the effective number of turns of the field winding of the rotary converter at starting.

In witness whereof, I have hereunto set my hand this 29th day of May, 1907.

ERNST if. W. ALEXANDERSON.

\Vitnesses BENJAMIN B. HULL, HELEN Onroun. 

